The present invention relates in general to climate control systems for motor vehicles, and, more specifically, to efficient use of a floor-mode conditioned airflow.
Fuel efficiency and cost are important decision factors when purchasing a new vehicle. On the other hand, purchasers also want a climate control system that provides good comfort for the occupants with the ability to quickly warm up or cool down upon entering the vehicle. Meeting this demand becomes especially challenging for larger vehicles such as minivans and crossover models having more than two rows of seating.
For any particular model of vehicle (i.e., a platform), the manufacturer may produce several variants with different levels of content and sold at correspondingly different prices. For a platform with second and third rows of seating, an auxiliary HVAC case dedicated to providing a conditioned airflow to the rear seats may be provided as an option. A lower cost version may also be provided without the auxiliary HVAC, in which case heating ducts feeding conditioned airflow from the main HVAC case in the front of the vehicle to the second and third rows is usually provided. The heated or cooled air always flows to all of the first, second, and third row floor outlets front HVAC, thereby fully loading the front HVAC unit regardless of whether all the rows are occupied. This results in inefficient use of energy and causes the burning of extra fuel and/or extra electrical consumption from the battery. It would be desirable to optimize energy usage while providing for greater thermal comfort and performance.